Diagnostics

mi_img_create, mi_img_open, mi_img_close, mi_img_read, and mi_img_write return miFALSE if an error occurred, or miTRUE if the call succeeded. mi_img_alloc returns 0 if there is no memory, and a nonzero pointer otherwise. mi_img_err_msg returns nothing. All others return values, there are no errors. There is a global variable img_debug that can be set to values 0…3 for automatic printing of diagnostics, and a routine mi_img_debug that sets this variable:

0	no automatic diagnostics
1	diagnostics for create, open, and close
2	same as 1, also prints file format and size
3	same as 2, also reports scanline r/w problems

img_debug is initialized to 0. All messages are printed using the mi_debug printing routine. The library contains sanity checks that prevent operations on invalid miImg_file structs that have not been opened, or have been opened twice.

The mi_img_err_msg function prints an error message for the argument miImg_file structure, if an error occurred. The error is printed using mi_error.